1. Stage 3: Oxidative Phosphorylation
Cellular Respiration
Stage 3: Oxidative Phosphorylation

2. Oxidative Phosphorylation
Electron Transport Chain
Chemiosmosis
Occurs in inner membrane of mitochondria
Produces ATP by oxidative phosphorylation via chemiosmosis
H+ ions pumped across inner mitochondrial membrane
H+ diffuse through ATP synthase (ADP  ATP)

3. Electron Transport Chain (ETC)
Collection of molecules embedded in inner membrane of mitochondria
Tightly bound protein + non-protein components
Alternate between reduced/oxidized states as accept/donate e-
Does not make ATP directly
Ease fall of e- from food to O2
2H+ + ½ O2  H2O

4. As electrons move through the ETC, proton pumps move H+ across inner mitochondrial membrane

5. Chemiosmosis: Energy-Coupling Mechanism
Chemiosmosis = H+ gradient across membrane drives cellular work
Proton-motive force: use proton (H+) gradient to perform work
ATP synthase: enzyme that makes ATP
Use E from proton (H+) gradient – flow of H+ back across membrane

6. Chemiosmosis couples the ETC to ATP synthesis

7. H+ pumped from matrix to intermembrane space
oxidative phosphorylation
uses
generates
chemiosmosis
which couples
proton gradient
ATP
uses E
to produce
called
redox reactions
H+ pumped from matrix to intermembrane space
proton motive force of
ETC
drives
in which H+
e- passed down E levels
through
ATP synthase
to final e- acceptor
O2  H2O

8. ATP yield per molecule of glucose at each stage of cellular respiration

9. BioFlix: Cellular Respiration

10. Anaerobic Respiration: generate ATP using other electron acceptors besides O2
Final e- acceptors: sulfate (SO4), nitrate, sulfur (produces H2S)
Eg. Obligate anaerobes: can’t survive in O2
Facultative anaerobes: make ATP by aerobic respiration (with O2 present) or switch to fermentation (no O2 available)
Eg. human muscle cells

11. Fermentation = glycolysis + regeneration of NAD+

12. Glycolysis Fermentation Respiration
Without O2
O2 present
Fermentation
Respiration
Keep glycolysis going by regenerating NAD+
Occurs in cytosol
No oxygen needed
Creates ethanol [+ CO2] or lactate
2 ATP (from glycolysis)
Release E from breakdown of food with O2
Occurs in mitochondria
O2 required (final electron acceptor)
Produces CO2, H2O and up to 32 ATP

13. Types of Fermentation Pyruvate  Ethanol + CO2 Ex. bacteria, yeast
Alcohol fermentation
Lactic acid fermentation
Pyruvate  Ethanol + CO2
Ex. bacteria, yeast
Used in brewing, winemaking, baking
Pyruvate  Lactate
Ex. fungi, bacteria, human muscle cells
Used to make cheese, yogurt, acetone, methanol
Note: Lactate build-up does NOT causes muscle fatigue and pain (old idea)

14. Various sources of fuel
Carbohydrates, fats and proteins can ALL be used as fuel for cellular respiration
Monomers enter glycolysis or citric acid cycle at different points

15. Phosphofructokinase:
Allosteric enzyme that controls rate of glycolysis and citric acid cycle
Inhibited by ATP, citrate
Stimulated by AMP
AMP+ P + P ATP

16. Respiration: Big Picture

17. aerobic cellular respiration
ENERGY
aerobic cellular respiration
(with O2)
anaerobic (without O2)
glycolysis
(cytosol)
mitochondria
Fermentation
(cytosol)
pyruvate oxidation
ethanol + CO2
(yeast, some bacteria)
citric acid cycle
substrate-level phosphorylation
lactic acid
(animals)
ETC
oxidative phosphorylation
chemiosmosis

18. Glycolysis & Citric Acid Cycle

19. Oxidative Phosphorylation
Electron Transport Chain
Chemiosmosis

20. What’s the Difference? Substrate-level phosphorylation
Oxidative phosphorylation
Add Pi from one compound to ADP directly
Energy comes from the chemical reaction itself
“no middle man”
Uses:
Glycolysis
Krebs Cycle
Uses a “middle man” = NADH and FADH and the pumping of electrons to generate an electrochemical gradient to make ATP
Pi come from a pool of phosphates
Uses:
ETC + Chemiosmosis

22. Worksheet Practice

23. Quizlet https://quizlet.com/_3whks7
Play/Review with the flashcards first
Then select 1 game to play either alone or with a partner
Record your time: ______

24. Bean Brew…an Investigative Case
Close Read
? And !
Highlight key vocab terms
Work to complete the questions throughout the investigation (Parts I-II)in your lab groups.
Answer in complete sentences in the packets.
Use the textbook to refer to the indicated diagrams in ch. 7, 8, and 9.
Choose either Part IV or V to complete at home. Due date = Monday Nov. 6

25. “The Mystery of the Seven Deaths”
Read the Case Study and answer the questions.
Discuss with someone near you if you aren’t sure!
Write your answers in the white space but be sure to use COMPLETE sentences that clearly address the question.